The present invention relates to a channel for the guidance or conveying of fibers, fiber slivers or yarns in a spinning machine, an open-end spinning device with such a channel, as well as a process for the manufacture of such a channel. A spinning machine with an open-end rotor spinning device is known from DE-A 37 34 544, in which the rotor housing is closed by means of a rotor lid, whereby the rotor lid and the channel located therein for the conveying of fibers into the spinning rotor are made in one piece by means of a molding or injection molding process. In order to obtain a bent form of the channel, the channel for fiber conveying is designed in such a manner in the open-end spinning device described in DE-A 37 34 544 that its two openings, the input opening for fibers and the output opening, are larger than the area of the channel between them, which is generally called the fiber feeding channel in open-end spinning machines. As a result, the cores which are necessary for the injection molding process which eventually produce the inside of the fiber feeding channel can be pulled out again from the form or from the completed rotor lid after the production of said rotor lid is completed. The molding method, in particular the injection molding method, makes it possible to produce the rotor lid in greater numbers, it being possible to produce the lid at the same time with lower tolerances and nevertheless economically. Such a channel has nevertheless the disadvantage that the design of its inner contour is very much restricted. In addition, the surface quality of the inside contour of the channel is not sufficiently high and must often be machined at high cost. A continuous transition between different cross-sections, e.g. also in the area of a diameter reduction of the channel or an enlargement of the diameter, is not possible or possible only with great difficulty.